Something weird just happened, it had accidentally clicked use on a fish it was dropping and kept trying to use it on the fishing spot, just standing there spamming it and getting 'nothing interesting happens'.
EDIT: It also seemed to only drop Leaping Sturgeons when I had Leaping Salmons selected
EDIT2: Seems to be a regular occurance that it gets stuck after having accidentally clicked use instead of drop, I do have shift-click dropping enabled.